This is the first time that I will cook meat. My question is that in the method of boiling/simmering meat, the foam of fats I see and I remove it with a large spoon. If I use another method for cooking meat (such as frying or grilling) will the fat remain in the meat?
What you are skimming certainly is some fat, but it is probably mostly comprised of denatured proteins. We can't answer questions about healthy or not on this site. That is all relative to you and your preferences. Salt enhances flavor. Salting well in advance, removes moisture, concentrates flavor, and enhances flavor by penetrating the meat.